Hinge for hinged stirrup fabric

ABSTRACT

Fabric for reinforcing concrete pipe and the like including stirrup members for anchoring the fabric in the concrete which are joined to the fabric by hinge means. The stirrup members are rotatable between a non-erect position generally parallel to the fabric and an erect position generally normal to the fabric. The hinge means include two cantilever arms for hingedly securing the stirrup members to the fabric, for biasing the stirrup members into the non-erect position, and for resisting any further rotation of the members once they are in the erect position. One arm lies on one side of the stirrup member and tends to bias the stirrup member into its non-erect position. The other arm lies on the other side of the stirrup member and serves as a stop when the stirrup member is erected. As the stirrup member is erected, the first arm slides around the base of the stirrup member and its end engages the stirrup member on the same side as the second arm, but below the axis of rotation of the stirrup member. This locks the stirrup member against rotation back to its non-erect position.

United States Patent [191 Henry et al.

[ 1 HINGE FOR HINGED STIRRUP FABRIC [75] Inventors: Mort W. Henry; Daniel J. Borodin,

both of Detroit, Mich.

[731 Assignee: New York Wire Mills C0rp.,

Tonawanda, NJ.

[22] Filed: July 23, 1973 [21] Appl. No.: 381,478

[52] US. Cl. 138/175 [51] Int. Cl. F161 9/08 [58] Field of Search 138/175, 176; 52/D1G. 7,

[56] References Cited UNITED STATES PATENTS 2,227,153 12/1940 Prosser 138/175 X 3,411,544 11/1968 Keyser 138/175 Primary Examiner-Jerry W. Myracle Attorney, Agent, or Firm-Price, Heneveld, l-luizeng & Cooper June 11, 1974 [5 7] ABSTRACT Fabric for reinforcing concrete pipe and the like including stirrup members for anchoring the fabric in the concrete which are joined to the fabric by hinge means. The stirrup members are rotatable between a non-erect position generally parallel to the fabric and an erect position generally normal to the fabric. The hinge means include two cantilever arms for hingedly securing the stirrup members to the fabric, for biasing the stirrup members into the non-erect position, and for resisting any further rotation of the members once they are in the erect position. One arm lies on one side of the stirrup member and tends to bias the stirrup member into its non-erect position. The other arm lies on the other side of the stirrup member and serves as a stop when the stirrup member is erected. As the stirrup member is erected, the first arm slides around the base of the stirrup member and its end engages the stirrup member on the same side as the second arm, but below the axis of rotation of the stirrup member. This locks the stirrup member against rotation back to its non-erect position.

26 Claims, 11 Drawing Figures HINGE FOR HINGED STIRRUP FABRIC This invention relates to fabric for reinforcing concrete pipe and the like, and, more particularly, to means for hingedly securing projecting stirrup members to the reinforcing fabric.

BACKGROUND OF THE INVENTION The concrete pipe industry, as well as other concrete forming industries, generally utilize fabrics made from steel or other rigid materials located within the concrete to reinforce and strengthen the ultimate product. Such internal reinforcing fabrics are generally formed into the appropriate shape, fitted within a concrete mold, and enclosed within the concrete which is poured into the mold. A revolutionary advance has recently occurred in the reinforcing fabric industry wherein projecting stirrup members for anchoring the fabric in the poured concrete are hingedly secured to the fabric such that they remain generally parallel to the fabric during transportation and roll forming of the fabric but may be rotated to the erect, anchoring position immediately'prior to the pouring of the concrete. The hinged mounting of such stirrup means has obviated the tedious, time-consuming job of welding these anchoring members to the fabric in preparation for pouring, This hinge mounting conceptis fully explained and disclosed in copending application, Ser. No. 300,114, entitled STIRRUP FABRIC AND METHOD FORFORMING PIPE REINFORCEMENT, invented by Wilbur E. Tolliver, filed Oct. 24, 1972, and assigned to the same assignee as the present invention. The disclosure of this copending application is incorporated by reference herein.

There are several basic requirements relating to the hinge mounting of the stirrups in such fabric. First, since the reinforcing fabric is manufactured to be generally planar, it is necessary that the hinged stirrup members be maintained generally parallel to the fabric during shipping and transportation. Shouldthe'hinged stirrups be allowed to rotate to their erect, anchoring positions prior to their insertion in the pipe forming molds, great difficulty would be encountered in transporting and storing the fabric including the hinged members thereby increasing the overall costs asso- Y ciated therewith.

Further, the reinforcing fabric is generally formed into appropriate shapes for inclusion in the various pipes and other products by passing the fabric through forming rollers. It is necessary that any hinge means prevent the stirrups from rotating to their erect positions during such forming. If the members were to become erect during such forming, the forming machinery could be jammed or completely ruined by the extending, erect stirrup members.

-Once the fabric has been transported to the pipe forming location, it is necessary to rotate the hinged members to their erect positions. It is essential that the members be kept in this erect orientation during the pouring'of the concrete therearound to provide the necessary anchoring function. If the members were allowed to return to their non-erect positions during the pouring, the entire object and function of the anchoring stirrups would be lost.

Therefore, in order to accomplish the desired anchoring function, the stirrup members must be retained in their non-erect positions during shipment and transportation as well as during any roll forming of the entire fabric. On the other hand, it is essential that when the stirrup members are rotated to their erect positions immediately prior to the pouring of the concrete, that they be retained in their erect positions in order .to accomplish their anchoring functions.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a hinge means for hingedly securing anchoring stirrup members to a fabric for reinforcing concrete pipe and the like, the hinge means biasing the stirrup members into a non-erect position generally parallel to the reinforcing fabric. Once the stirrup members have been rotated to the erect position, the hinge means retain the stirrup members in the erect position and resist any further rotation back to the non-erect position.

The hinge means includes two arms in engagement with two of the stirrup projections defined by the stirrup member. One of the lateral arms engages a top surface (as viewed in FIG. 3) of one of the stirrup projections thereby biasing the entire stirrup member into its non-erect position. The other of the lateral arms engages a bottom surface of another stirrup projection. Once the stirrup member has been rotated to its erect position, the lateral arms engage recesses in the stirrup projections on opposite sides of the axis of rotation of the stirrup member to prevent further rotation of the stirrup member and to retain the stirrup member in its erect position.

Inthe preferred embodiment, a central cantilever arm extends from'the base of the hinge over a tie rod which connects several stirrup projections secured thereto; The central arm biases the tie rod against the several supporting fabric strands and hingedly retains the entire stirrup member thereon.

In the preferred embodiment, the tie rod also includes an offset section having an irregular, generally BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a concrete pipe including reinforcing fabric having hinged stirrup projections rotated to their erect positions;

FIG. '2 is a cross-sectional view of a concrete pipe including a roll formed reinforcing fabric and separate fabric mats secured thereto, the mats including stirrup members rotated to their erect positions;

FIG. 3 is, a plan view of a portion of the reinforcing fabric including hinged stirrup members and projections, some of the stirrup members being shown in the non-erect position and others shown in the erect position;

FIG. 4 is a broken, cross-sectional, side view of a portion of the reinforcing fabric including hinged stirrup projections and binge members therefor taken along the plane lV--IV of FIG. 3;

FIG. 5 is a fragmentary, cross-sectional, side view of a portion of the reinforcing fabric similar to that shown in FIG. 4 but after the fabric has been formed;

FIG. 6 is an enlarged, fragmentary, corss-sectional view of the offset portion of the tie rod of one of the stirrup members and a portion of the hinge member in mating engagement therewith as taken along the plane VlVI of FIG. 3;

FIG. 7 is a fragmentary, cross-sectional, side view of one of the stirrup projections engaged in the non-erect position by a portion of the hinge member as taken along plane VII-VII of FIG. 3;

FIG. 8 is a fragmentary, corss-sectional, side view of a second stirrup projection engaged in the non-erect position by a second portion of the hinge member taken along plane VIIIVIII of FIG. 3;

FIG. 9 is a fragmentary, cross-sectional, side view of a stirrup projection and hinge member similar to that of FIG. 7, but shown in the erect position as taken along the plane IX-IX of FIG. 3;

FIG. 10 is a fragmentary, cross-sectional, side view of a stirrup projection and hinge member similar to that of FIG. 8, but shown in the erect position as taken along the plane XX of FIG. 3; and

FIG. 1 1 is a fragmentary, cross-sectional, side view of the hinge member shown in FIGS. 3-l0 engaging the offset section of the tie rod of one of the stirrup members in the erect position as taken along the plane XIXI of FIG. 3.

DESCRIPTION O THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2, typical reinforced concrete pipes 10 and 12 are shown in cross section including two types of reinforcing fabrics. Pipe 10 includes' a reinforcing fabric 14 which has been formed into a generally elliptical cross section prior to being molded within the pipe. Fabric 14 includes stirrup members having stirrup projections 16, the members being hingedly secured directly to the fabric via the hinge means of the present invention. Pipe 12 includes a reinforcing fabric 18 which again has been roll formed into a generally elliptical cross section. However, instead of the stirrup members or projections being hinged directly to the fabric 18, separate fabric mats 20, including hinged stirrup projections 22 hinged thereto via the hinge means of the present invention, are separately secured via welding or the like to the crown and invert areas of the fabric as shown in FIG.

As shown in FIG. 3, the reinforcing fabric of the type inserted in pipes 10 and'l2 typically comprises a plurality of longitudinally extending strands 24 and a plurality of circumferentially extending strands 26. As described in the copending application referred to above, Ser. No. 300,114, entitled STIRRUP FABRIC AND METHOD FOR FORMING PIPE REINFORCE- MENT, invented by Wilbur E. Tolliver, and filed Oct. 24, 1972, the disclosure of which is incorporated by reference herein, a plurality of stirrup members 28 for anchoring the reinforcing fabric in the concrete are hingedly secured generally parallel to the longitudinal strands 24. This hinge mounting is achieved in the preferred embodiment of the present invention by hinges 40. Hinge member 40a is shown biasing stirrup member 28a into the non-erect position while hinge member 201) biases and retains member 28b in the erect position. Although the stirrup members may be of many varied shapes, as described in the copending application, the stirrup members typically are as shown in FIG. 3. Members 28 each comprise a tie rod 30 which ex- .tends generally parallel to the longitudinal strands 24 and a plurality of stirrup projections or rods 32 which are secured via welding or the like generally perpendicularly to the axis of the tie rod. These members are rotatable about hinge axes comprising generally the axes of the tie rods 30 from a non-erect position, wherein the stirrup projections 32 are generally parallel to the remainder of the fabric to an erect position wherein the projections extend generally normally to the remainder of the fabric.

Referring now to FIGS. 3 and 4, hinge members 40 each comprise a base area 42 welded or otherwise fixedly secured to a longitudinal strand 24 and three arms extending therefrom into engagement with the stirrup members 28. Base 42 has a contoured cross section which generally corresponds to the circular cross section of the longitudinal strands 24 as shown in FIG. 4. The three cantilever arms include a central cantilever hinge arm 44 having an end which extends over tie rod 30 and biases the tie rod downwardly against the top surfaces of circumferential strands 26. On either side of the central hinge arm 44, a side cantilever arm 46 and a stop arm 48 engage two of the individual stirrup projections 32 on opposite sides thereof. Side arm 46 tends to bias stirrup member 28 into its non-erect position while stop arm 48 limits the extent to which stirrup member 28 can be rotated into its erected position.

As shown in FIG. 3, side arm 46 is tapered toward its free end 50 but is necked down in an area 52 immediately adjacent to that free end. The entirety of the hinge member 40, including cantilever arms 44-48, is stamped or otherwise formed in one-piecefrom spring steel. Arm 46 is tapered at 52 to provide maximum force for a given deflection without producing a permanent set. Arm 46 engages the top of the extending end 54 of one of the projections 32, as shown in FIG. 8, thereby biasing it in the direction shown by arrow B into its non-erect position. Surface 56 of end 54 is engaged by arm 46 when projection32 is in its non-erect position. A ledge 58 in end 54 is engaged by arm 46 when the projection is in its erect position as shown in FIG. 10. A curvilinear surface 60 from ledge 58 to the base of projection 32 allows the end of arm 46 to slide easily thereover during the rotation of the stirrup member. Assuming for purposes of explanation that projection 32 is substantially horizontal when in the non-erect position as shown in FIG. 8, ledge 58 is inclined approximately 5 with respect to the vertical. This allows the arm 46 to lie flat therealong in the erect position as shown in FIG. 10. Consequently, the end 50 of arm 46 securely engages or bites into the corner of the recess to prevent the projection from being rotated back to its non-erect position, i.e., in the direction of arrow B in FIG. 10. Thus, it will be understood that arm 46 serves two separate functions. It biases the stirrup projection 32 into its non-erect position, as shown on the hinge member 40a in FIG. 3 and in FIG. 8, and acts as a supporting strut biasing the stirrup I projection into the erect position and preventing any rotation back to the non-erectposition, as shown on hinge member 40b in FIG. 3 and in FIG. 10.

Stop cantilever arm 48 acts as a stop member and as a supporting strut when stirrup member 28 is erected. As shown in FIGS. 3 and 7, stop arm 48 engages one of theprojections 32 on the bottom side of end 62 thereof along an inclined surface 64. Given the resilient nature of the material from which the hinge members 40 are made, arm 48 may slightly bias the end 62 in the direction indicated by arrow C in FIG. 7. Normally, however, this biasing force is not sufficient to overcome the forces exerted by hinge arm 44 and arm 46 which retain the stirrup member 28 in the non-erect position. When the stirrup members are rotated in the direction indicated by arrow C in FIG. 7, by applying a sufficient force thereto, the end 49 of stop arm 48 slides along inclined surface 64 over a raised area or ridge 66 and into a recess or notch 68. As is best seen FIG. 9, the end 49 of arm 48 securely engages or bites into the surface of notch 68 when the rod 32 reaches the erect position. Arm 48 acts as a generally rectilinear strut to prevent further rotation of projection 32 past the erect position. In this respect, stop arm 48 has generally parallel sides in the plan view as shown in FIG. 3, thereby concentrating more material and greater rigidity in stop arm 48.

As will now be understood, the cantilever arms cooperate to function as a capturing means which captures or traps a pair of the stirrup projections in the erect position. Rotation of the stirrup member in either direction about the hinge axis is prevented by the engagement of the arms with recesses 58 and 68, located on opposite sides of the axis of rotation of stirrup member 28. Thus, the stirrup projections are securely held in the erect position to perform their anchoring function in the concrete products.

Helping to bias the stirrup member 28 and to prevent rotation of the stirrup member in either its non-erect or erect positions is the contoured end 70 of the central cantilever hinge arm 44 and a contoured mounting area or section 72 of the tie rod 30. As shown in FIGS. 4-6 and 11, tie rod 30 generally has a circular cross section while contoured mounting area 72 is generally pressed or stamped centrally therein between the two stirrup rods or projections 32 which are engaged by side arm 46 and stop arm 48. Contoured mounting section 72 has a generally square cross section with rounded corners 73 and recessed areas 74. therebetween. The entire contoured mounting section 72 has an axis which is offset from the general hinge axis of the stirrup member 28.

The-end 70 of central arm 44 is shaped to correspond to the-contour of the offset mounting section 72. Thus, end 70 includes integral portions 76 and 78 disposed substantially at right angles to one another defining a substantially right angle, rounded corner 79 on the inside therebetween.

Accordingly, as shown in FIGS. 4 through 6, when the stirrup members 28 are in their non-erect positions, one rounded corner 73 of offset mounting section 72 will engage the internal corner 79 with portions 76 and 78 engaging two other corners 73 and 73" of section 72. The spring biasing action of hinge arm 44 pressing downwardly on mounting section 72 tends to retain section 72 and tie rod 30 in the position shown with the corners 73, 73' and 73" tending to resist any rotation of the tie rod. Further, the distance mounting section 72 is offset from the hinge axis of tie rod 30 provides a greater moment against which the end 70 of the spring arm 44 acts. Consequently, the"engager nent of end with section 72 tends to resist any rotation of the tie rod 30 and stirrup member 28. As will be seen in FIG. 4, in the non-erect position. arms and 48 define an angle Y therebetween when theyare correctly positioned on opposite sides of the ends of the-respective stirrup rods 32. This angle Y is approximately bisected by the central hinge arm 44 in biasing engagement with section 72 of tie rod 30. 1

Although the biasing action of the hinge 40 against the stirrup members 28 is sufficient to normally prevent rods or projections 32 may be grasped and a sufficient force exerted thereon to overcome the biasing action. When sufficient force is exerted, the stirrup members 28 may be rotated, via stirrup rods 32, against the biasing force of the offset mounting section 72 and-end 70 of hinge arm 44 and against the biasing action of side arm 46 against end 54, to the erect position shown in FIG. 4. Such rotation forces rounded corner 73' into the internal corner 79 of end 70 and causes arm 44 to bow slightly upwardly (FIG. 11) in a spring-like manner in order to accommodate the changed position of the offset mounting sections 72. Accordingly, the slight bowing of arm 44 and the offset position of section 72 force tie rod 30 against the circumferential strands 26 with a greater force than when the arm 44 is engaging the offset section in the non-erect position. Thus, the hinge member 40 securely retains the stirrup members 28 against the reinforcing fabric when in the erect position. Further, it will be understood that the various biasing means included on the hinge members securely retain the hinged stirrup members 28 in the erect position by preventing any further rotation of the members back to a non-erect position via arms 44, 46 and 48.

A further feature of the hinge member 40 is shown in FIG. 5. As mentioned above, it is often necessary to roll form the reinforcing fabric for concrete pipe. As shown in FIG. 5, the reinforcing fabric including the hingedly secured stirrup members 28 and hinge members 40 of the present invention may be rolled into a curvilinear cross-sectional shape, such as the elliptical shape shown in FIGS. land 2. The hinges 40 generally lie within the general plane of the longitudinal members 24 and do not interfere with the rolls. Hinges 40 securely retain the stirrup rods or projections 32 in their non-erect position during rolling. Accordingly, when the reinforcing fabric is roll formed, the stirrup rods will be retained in their non-erect position to prevent rotation to an erect or partially erect position which could severely damage the roll forming machinery and mange] the stirrup fabric. Therefore, the present hinge means allow the reinforcing fabric to be assembled with the hinge stirrup members 28 and hinge members 40 prior to roll forming but allow the hinge stirrup members to be erected to their anchoring positions in the manner described after such a forming operation.

As will now be understood, the present inventivehinge means for hingedly securing stirrup members to reinforcing fabric for concrete pipes and the like allows the stirrup members to be securely biased into their non-erect positions for storage, transportation and roll forming purposes but also allows these members to be rotated to their erect position and securely retained therein immediately prior to insertion into aconcrete mold. The hinges 40 may be easily and inexpensively stamped from mild, annealed steel and may be welded to the reinforcing fabric by automatic machines. Ac-

cordingly, the hinges 40 provide the desired results of upwardly, downwardly, top-and bottom, etc., are in-- cluded for explanation purposes only and are not intended to limit the scope of the invention.

While one form of the invention has been shown and described, other forms will now be apparent tothose skilled in the art. In the broader aspects of the invention, the stirrup members, for example, might be a single generally sinusoidal strand of wire or a generally sinusoidal strand joined to a tie rod. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely-for illustrative purposes and are not intended to limit the scope of the invention which is defined by the claims which follow.

rup members to said fabric, said hinge means including first and second arms, said first arm lying-on a first side of said stirrup member when said stirrup member is in its non-erect position, and said second arm lying on the second side of said stirrup member when said stirrup member is in its non-erect position; said stirrup member including portions extending below and above its hinge axis; the length of said first and second arms being such that when said stirrup member is rotated into its erect position, the end of said first arm slides around the bottom of said stirrup member and engages said stirrup member below said axis of rotation thereof and on said second side thereof, the end of said second arm engaging said stirrup member generally above said axis of rotation on said second side thereof,,whereby said stirrup member is locked against further rotation.

2. The fabric of claim 1 in which said stirrup member includes a notch on said second side thereof, said notch being positioned generally above said hinge axis of said stirrup member whereby the end of said second arm engages said notch when said stirrup member is rotated to its generally erect position.

3. The fabric of claim 2 in which said stirrup member includes a ledge positioned generally below said hinge axis whereby said first arm comes to rest against said ledge when said stirrup member is moved to its erect position.

4. The fabric of claim 3 in which said stirrup member includes a first contoured surface generally extending from said ledge to the base of said stirrup member whereby the end of said first arm slides over said contoured surface as said stirrupmember is being erected.

5. The fabric of claim 4 in which said stirrup member includes a second contoured surface extending generally from the base thereof generally to said notch whereby the end of said second arm slides over said contoured surface as said stirrup member is erected.-

6. The fabric of claim 5 in which said stirrup member comprises an elongated tierod oriented generally parallel to the longitudinal strands of said fabric and a plurality of separate stirrup projections joined to said tie rod and projecting therefrom.

7. The fabric of claim 6 in which each of said stirrup projections projects a short distance below said tie rod as well as projecting a substantialdistance above said tie rod, said first arm lying on said first sideof one of said stirrup projections and said second arm, lying on said second side of another of said stirrup projections.

8. The fabric of claim 7 in which said ledge and said first contoured surface are on said stirrup projection engaged by said first arm and said notch and said second contoured surface are on said stirrup projection engaged by said second arm.

9. The fabricof claim 1 in which said hinge means inciudes a third arm shaped to embracingly engagesaid stirrup member and hingedly hold it to said fabric.

10. The fabric of claim 9 in which the end of said third arm is generally V-shaped in configuration, said stirrup member being embracingly received within said V-shaped portion.

11. The fabric of claim 10 in which said stirrup member comprises an elongated tie rod oriented generally parallel to the longitudinal strands of said fabric and a plurality of separate stirrup projections joined to said tie rod and projecting therefrom.

12. The fabric of claim 11 in which said tie rod includes a mounting portion offset from the main axis thereof, said mounting portion being embracingly received within said generally V-shaped end of said third arm.

13. The fabric of claim 10 in which said hinge means includes a base joined to a longitudinal defining strand, said first, second and third arms extending outwardly from said base.

14. The fabric of claim 13 in which said hinge means is made of spring steel. v

15. A frabric for reinforcing concrete pipe or the like, said fabric including a plurality of longitudinal and circumferential cage defining strands and comprising: a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for hingedly. joining said stirrup members to said fabric whereby they can be rotated from a non-erect to an erect position; said hinge means including bias means biasing said stirrup member into a non-erect position and stop means for positively limiting further rotation of said stirrup member when it is rotated into said erect position.

16. The fabric of claim 15 in which said stop means positively limits further rotation of said stirrup member in either direction once it is moved into its erect position.

17. The fabric of claim 16 in which said stop means includes a first arm lying on a firstside of said stirrup member when said stirrup member is in its non-erect position and a second arm lying on a second side of said stirrup member when said stirrup member is in its nonerect position; said bias means also including said sec-. ond arm lying on said second side of said stirrup member when said stirrup member is in its non-erect positron.

18. The fabric of claim 17 in which said bias means further includes a third arm, said third arm including means embracingly engaging said stirrup member.

19. A fabric for the reinforcing of concrete pipe or the like including a plurality of longitudinal and circumferential cage defining strands; at least one stirrup member hingedly joined to said fabric and having at least two stirrup projections; hinge means for hingedly securing said stirrup member to said fabric; said hinge means including a base secured to one of said strands and cantilever means extending from said base and engaging said stirrup member for resisting rotation of said hinged stirrup member.

20 The fabric of claim 19 wherein said cantilever means and stirrup member include means for capturing and retaining said stirrup member in said erect position once it has been rotated to said erect position.

21. The fabric of claim 19- wherein said stirrup member includes a tie rod to which said stirrup projections are secured therealong; said cantilever means including a plurality of cantilever arms; one of said plurality of cantilever arms extending between said base and said tie rod to hingedly secure said tie rod to said fabric; said one cantilever arm including a section contoured to fit over and receive at least a portion of said tie rod whereby said tie rod is rotatable between said contoured section and a plurality of said strands of said fabric.

22. The fabric of claim 21 wherein said tie rod has an axis of rotation and includes a length therealong which is offset from said axis; said length having an irregular cross section; said contoured section of said one cantilever arm having a contour substantially similar to said length whereby said contoured section mates with said length to resist rotation of said tie rod.

23. The fabric of claim 19 wherein said cantilever means includes a plurality of cantilever arms; two of said plurality of cantilever arms engagingtwo of said stirrup projections; one of said two cantilever arms biasing one of said stirrup projections toward a non-erect position generally parallel with said fabric and the other of said two cantilever arms serving primarily as a stop to limit rotation of said stirrup member when it is erected.

24. The fabric of claim 23 wherein said two stirrup projections include recess means engaged by said cantilever arms when said stirrup member is in its erect position; said engagement of said recess means by said arms resisting rotation of said stirrup member from said erect position.

25. The fabric of claim 19 wherein said cantilever means include a plurality of cantilever arms; one of said plurality of cantilever arms including means for resisting any rotation of said stirrup member, a second of said plurality of cantilever arms biasing one of said stirrup projections into a non-erect position generally parallel to said fabric, and a third of said plurality of cantilever arms serving primarily as a stop to limit rotation of said stirrup member when it is erected.

26. The fabric of claim 25 wherein said second and third cantilever arms are spaced along said base and extend therefrom generally parallel to one another in generally the same direction; said one cantilever arm extending from said base generally parallel to, in gener-. ally the same direction as, and between said second and third arms. 

1. A fabric for reinforcing concrete pipe or the like, said fabric including a plurality of longitudinal and circumferential defining strands and comprising: a plurality of elongated stirrup members hingedly joined to said fabric for rotation from a nonerect to an erect position, each stirrup member defining a plurality of stirrup projections; hinge means for hingedly joining said stirrup members to said fabric, said hinge means including first and second arms, said first arm lying on a first side of said stirrup member when said stirrup member is in its non-erect position, and said second arm lying on the second side of said stirrup member when said stirrup member is in its nonerect position; said stirrup member including portions extending below and above its hinge axis; the length of said first aNd second arms being such that when said stirrup member is rotated into its erect position, the end of said first arm slides around the bottom of said stirrup member and engages said stirrup member below said axis of rotation thereof and on said second side thereof, the end of said second arm engaging said stirrup member generally above said axis of rotation on said second side thereof, whereby said stirrup member is locked against further rotation.
 2. The fabric of claim 1 in which said stirrup member includes a notch on said second side thereof, said notch being positioned generally above said hinge axis of said stirrup member whereby the end of said second arm engages said notch when said stirrup member is rotated to its generally erect position.
 3. The fabric of claim 2 in which said stirrup member includes a ledge positioned generally below said hinge axis whereby said first arm comes to rest against said ledge when said stirrup member is moved to its erect position.
 4. The fabric of claim 3 in which said stirrup member includes a first contoured surface generally extending from said ledge to the base of said stirrup member whereby the end of said first arm slides over said contoured surface as said stirrup member is being erected.
 5. The fabric of claim 4 in which said stirrup member includes a second contoured surface extending generally from the base thereof generally to said notch whereby the end of said second arm slides over said contoured surface as said stirrup member is erected.
 6. The fabric of claim 5 in which said stirrup member comprises an elongated tie rod oriented generally parallel to the longitudinal strands of said fabric and a plurality of separate stirrup projections joined to said tie rod and projecting therefrom.
 7. The fabric of claim 6 in which each of said stirrup projections projects a short distance below said tie rod as well as projecting a substantial distance above said tie rod, said first arm lying on said first side of one of said stirrup projections and said second arm lying on said second side of another of said stirrup projections.
 8. The fabric of claim 7 in which said ledge and said first contoured surface are on said stirrup projection engaged by said first arm and said notch and said second contoured surface are on said stirrup projection engaged by said second arm.
 9. The fabric of claim 1 in which said hinge means includes a third arm shaped to embracingly engage said stirrup member and hingedly hold it to said fabric.
 10. The fabric of claim 9 in which the end of said third arm is generally V-shaped in configuration, said stirrup member being embracingly received within said V-shaped portion.
 11. The fabric of claim 10 in which said stirrup member comprises an elongated tie rod oriented generally parallel to the longitudinal strands of said fabric and a plurality of separate stirrup projections joined to said tie rod and projecting therefrom.
 12. The fabric of claim 11 in which said tie rod includes a mounting portion offset from the main axis thereof, said mounting portion being embracingly received within said generally V-shaped end of said third arm.
 13. The fabric of claim 10 in which said hinge means includes a base joined to a longitudinal defining strand, said first, second and third arms extending outwardly from said base.
 14. The fabric of claim 13 in which said hinge means is made of spring steel.
 15. A frabric for reinforcing concrete pipe or the like, said fabric including a plurality of longitudinal and circumferential cage defining strands and comprising: a plurality of elongated stirrup members hingedly joined to said fabric, each member defining a plurality of stirrup projections; hinge means for hingedly joining said stirrup members to said fabric whereby they can be rotated from a non-erect to an erect position; said hinge means including bias means biasing said stirrup member into a non-erect position and stop means for positively limiting further rotation of saId stirrup member when it is rotated into said erect position.
 16. The fabric of claim 15 in which said stop means positively limits further rotation of said stirrup member in either direction once it is moved into its erect position.
 17. The fabric of claim 16 in which said stop means includes a first arm lying on a first side of said stirrup member when said stirrup member is in its non-erect position and a second arm lying on a second side of said stirrup member when said stirrup member is in its non-erect position; said bias means also including said second arm lying on said second side of said stirrup member when said stirrup member is in its non-erect position.
 18. The fabric of claim 17 in which said bias means further includes a third arm, said third arm including means embracingly engaging said stirrup member.
 19. A fabric for the reinforcing of concrete pipe or the like including a plurality of longitudinal and circumferential cage defining strands; at least one stirrup member hingedly joined to said fabric and having at least two stirrup projections; hinge means for hingedly securing said stirrup member to said fabric; said hinge means including a base secured to one of said strands and cantilever means extending from said base and engaging said stirrup member for resisting rotation of said hinged stirrup member. 20 The fabric of claim 19 wherein said cantilever means and stirrup member include means for capturing and retaining said stirrup member in said erect position once it has been rotated to said erect position.
 21. The fabric of claim 19 wherein said stirrup member includes a tie rod to which said stirrup projections are secured therealong; said cantilever means including a plurality of cantilever arms; one of said plurality of cantilever arms extending between said base and said tie rod to hingedly secure said tie rod to said fabric; said one cantilever arm including a section contoured to fit over and receive at least a portion of said tie rod whereby said tie rod is rotatable between said contoured section and a plurality of said strands of said fabric.
 22. The fabric of claim 21 wherein said tie rod has an axis of rotation and includes a length therealong which is offset from said axis; said length having an irregular cross section; said contoured section of said one cantilever arm having a contour substantially similar to said length whereby said contoured section mates with said length to resist rotation of said tie rod.
 23. The fabric of claim 19 wherein said cantilever means includes a plurality of cantilever arms; two of said plurality of cantilever arms engaging two of said stirrup projections; one of said two cantilever arms biasing one of said stirrup projections toward a non-erect position generally parallel with said fabric and the other of said two cantilever arms serving primarily as a stop to limit rotation of said stirrup member when it is erected.
 24. The fabric of claim 23 wherein said two stirrup projections include recess means engaged by said cantilever arms when said stirrup member is in its erect position; said engagement of said recess means by said arms resisting rotation of said stirrup member from said erect position.
 25. The fabric of claim 19 wherein said cantilever means include a plurality of cantilever arms; one of said plurality of cantilever arms including means for resisting any rotation of said stirrup member, a second of said plurality of cantilever arms biasing one of said stirrup projections into a non-erect position generally parallel to said fabric, and a third of said plurality of cantilever arms serving primarily as a stop to limit rotation of said stirrup member when it is erected.
 26. The fabric of claim 25 wherein said second and third cantilever arms are spaced along said base and extend therefrom generally parallel to one another in generally the same direction; said one cantilever arm extending from said base generally parallel to, in generally the same direction as, and betWeen said second and third arms. 